That data plate pic is a photo of one still installed in a coach, taken several years ago. I don't have a real one in my collection of "bus stuff."
The factory riveted the data plate in the MC-9s to the interior roof above the driver's window on the left, in front of the OEM driver's light.
If your coach has cabinetry in that area, try to peek behind and see if it's still there.
The plates are aluminum sheet that have the info painted (silk-screened?) on, except for the VIN info - that's engraved. So you could have a sign shop make you one, using the photo as a template. You supply the aluminum sheet for them to work with. Be sure to change the VIN info to match your coach.
To get the proper sizing, when you click on the photo, it comes up full-size, so you can simply measure it.
FWIW & HTH. . .